CN2935667Y - Output overvoltage protection circuit of PFC circuit and TV set equipped with the circuit - Google Patents
Output overvoltage protection circuit of PFC circuit and TV set equipped with the circuit Download PDFInfo
- Publication number
- CN2935667Y CN2935667Y CNU2006200874340U CN200620087434U CN2935667Y CN 2935667 Y CN2935667 Y CN 2935667Y CN U2006200874340 U CNU2006200874340 U CN U2006200874340U CN 200620087434 U CN200620087434 U CN 200620087434U CN 2935667 Y CN2935667 Y CN 2935667Y
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- voltage
- pfc
- circuit
- pfc chip
- power supply
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Abstract
The utility model discloses the over-voltage protection circuit of PFC circuit and a TV set having the circuit; making the use of the characteristic that has the locking function when the voltage at the input terminal of the multiplier of PFC chip reaches the typical voltage value of the PFC chip, a switch controlling circuit is arranged between the multiplier input terminal of the PFC chip and the direct-current power source, the voltage output of PFC chip is grounded through a resistant voltage-distribution network, the connection joint between the voltage-distribution resistances is connected with the controlling end of the switch controlling circuit; when the output voltage of the PFC chip is higher than the limit value, the controlling terminal voltage of the switch controlling circuit reaches the open voltage value under the effect of the voltage-distribution resistance, and the controlling direct-current power source outputs the voltage to the multiplier input terminal of the PFC chip to reach the typical value defined by the PFC chip, thereby realizing the lock of the output voltage; therefore, the followed circuit is effectively protected.
Description
Technical field
The utility model relates to a kind of improvement of TV set circuit, specifically, relates to a kind of control circuit that the output voltage of Active Power Factor Correction pfc circuit is carried out overvoltage protection.
Background technology
Because the harmonic problem of electric network source is more and more paid attention to by people, so the power factor correction pfc circuit also is employed more and more.Pfc circuit generally is that the 220V alternating current is converted to direct current between 380～400V, and the filtering electrolysis that links to each other with the voltage output end of pfc circuit is generally selected 450V's for use.If the feedback of pfc circuit or sample circuit go wrong, tend to make the output voltage of PFC to reach the above even higher voltage of 450V, thereby cause the electrolysis explosion, the explosion consequence of big electrolysis is very serious, not only can damage equipment, even also can bring harm to consumer's personal safety.Therefore, how a protection point is set, when circuit occurs causing output voltage too high unusually, provides effective protection, just become a subject matter that must solve at present late-class circuit.
Summary of the invention
The utility model output voltage when solving in the prior art pfc circuit operation irregularity is too high; late-class circuit is caused the problem of damage; a kind of output over-voltage protection circuit of novel pfc circuit is provided; by the PFC output voltage is carried out online detection; when output voltage is higher than limit value; pfc circuit is quit work, thereby effectively protected the electrolysis of back level and other components and parts.
For solving the problems of the technologies described above, the utility model is achieved by the following technical solutions:
A kind of output over-voltage protection circuit of pfc circuit and have the television set of described circuit; comprise PFC chip and DC power supply; between multiplier input of described DC power supply and PFC chip, be connected with an ON-OFF control circuit; the voltage output end of PFC chip is through resistance pressure-dividing network ground connection; connected node between the divider resistance links to each other with the control end of described ON-OFF control circuit; when the output voltage of PFC chip is higher than limit value; the control end voltage of ON-OFF control circuit is issued to its cut-in voltage value in the effect of described divider resistance, and the control DC power supply reaches the representative value voltage of PFC chip definition to the multiplier input output of PFC chip.
As further qualification to technique scheme, in described ON-OFF control circuit, include the adjustable shunting a reference source of one or three ends device, the reference voltage end of the adjustable shunting a reference source of described three ends device connects the connected node between the described divider resistance, plus earth, negative electrode connects the base stage of a positive-negative-positive triode on the one hand through a resistance, connects described DC power supply through another resistance on the other hand; The emitter of described positive-negative-positive triode connects described DC power supply, and collector electrode connects multiplier input of PFC chip.
As to further the limiting again of technique scheme, between the reference voltage end of the adjustable shunting a reference source of described three ends device and ground, be connected with filter capacitor.Be in series with divider resistance between the emitter of described positive-negative-positive triode and the DC power supply or between multiplier input of collector electrode and PFC chip; Also be in series with switching diode between multiplier input of the collector electrode of triode and PFC chip.
Compared with prior art; advantage of the present utility model and good effect are: overvoltage crowbar of the present utility model utilizes the voltage of multiplier input of PFC chip to have these characteristics of lock function when reaching the representative value voltage of PFC chip; designed a kind of novel ON-OFF control circuit; prevented that effectively serious consequences such as electrolysis explosion from appearring taking place when unusual in pfc circuit work, also played the certain protection effect to late-class circuit simultaneously.Because the element that overvoltage crowbar adopted all is the lower resistance of cost, electric capacity, triode etc.; so on cost, can not increase a lot yet; more much lower than increasing a special overvoltage protection chip, for the application and the development of power technology provides a new thinking and method.
Description of drawings
Fig. 1 is the schematic diagram of the utility model overvoltage crowbar.
Embodiment
Below in conjunction with the drawings and specific embodiments the utility model is done explanation in further detail.
Among Fig. 1, DC power supply Vcc provides supply power voltage for the PFC chip, Mult FP is the multiplier input of PFC chip, when the voltage of multiplier input Mult FP reaches the representative value that the PFC chip sets (the representative value voltage of PFC chip of the present utility model is 8.8VTYPE), the PFC chip has lock function, and the utility model utilizes the locking of this function realization of PFC chip to PFC chip output voltage just.VIN is the voltage output end of PFC chip, through divider resistance R6, R7 ground connection.TL431 be one have good thermal stability can the adjustable shunting a reference source of three ends device U1, its reference voltage end links to each other with connected node between described divider resistance R6, the R7, and through filter capacitor C1 ground connection.The plus earth of TL431, negative electrode connects the base stage of positive-negative-positive triode Q1 through resistance R 4, and connects described DC power supply Vcc through resistance R 2.Resistance R 3 is connected between the negative electrode of DC power supply Vcc and TL431.The emitter of described positive-negative-positive triode Q1 connects described DC power supply Vcc through divider resistance R1, and collector electrode is connected the multiplier input Mult FP of described PFC chip with divider resistance R5 through the switching diode D2 of series connection.
Reference input voltage as TL431 is generally 2.5V, and VIN voltage that can be by needs and divider resistance R6, R7 regulate the magnitude of voltage of the reference input that is input to TL431.When the voltage VIN of PFC chip output is too high; under the dividing potential drop effect of resistance R 6, R7; the magnitude of voltage Vref that is input to the TL431 reference input meets or exceeds 2.5V; the TL431 conducting; thereby make between the E, B level of triode Q1 and produce voltage difference, make triode Q1 conducting, Vcc voltage is input to the multiplier input Mult FP of PFC chip by resistance R 1, triode Q1, diode D2 and resistance R 5; thereby make the pfc circuit locking, reach the purpose of overvoltage protection.
When the pfc circuit operate as normal, TL431 ends, and then triode Q1 is ended, and at this moment, overvoltage crowbar is failure to actuate, thereby has effectively guaranteed the operate as normal of pfc circuit.Have only the circuit abnormal of working as, when the PFC output voltage was too high, this protective circuit was just moved, and had effectively guaranteed the validity of overvoltage crowbar work.
Must note when this overvoltage crowbar of design: the PFC chip should select to have the chip of output lock function, and it is the chip realization of SMA-E1017 that PFC chip of the present utility model is selected model for use.Divider resistance R6, R7 must select high-precision resistance device, recommend 1% precision, to prevent the bad problem of consistency.Secondly, resistance R 7 must select for use shock-resistant, high voltage bearing resistance to realize, perhaps selects for use the mode of a plurality of resistance series connection to realize, be also noted that the interference problem when setting type, perhaps reasonably increase several filter capacitors,, influence the operate as normal of pfc circuit to prevent misoperation according to actual conditions.
The utility model has been realized when the pfc circuit operation irregularity effective restriction to its output voltage by adopting above-mentioned simple circuit configuration; thereby electric equipment products and late-class circuit are played a very good protection, can be widely used in the power circuit of television set.Certainly; above-mentioned explanation is not to be to restriction of the present utility model; the utility model also is not limited in above-mentioned giving an example, and variation, remodeling, interpolation or replacement that those skilled in the art are made in essential scope of the present utility model also should belong to protection range of the present utility model.
Claims (10)
1. the output over-voltage protection circuit of a pfc circuit; comprise PFC chip and DC power supply (Vcc); it is characterized in that: between multiplier input (Mult FP) of described DC power supply (Vcc) and PFC chip, be connected with an ON-OFF control circuit; the voltage output end of PFC chip (VIN) is through resistance pressure-dividing network (R6; R7) ground connection; divider resistance (R6; R7) connected node between links to each other with the control end of described ON-OFF control circuit; when the output voltage of PFC chip is higher than limit value; the control end voltage of ON-OFF control circuit reaches its cut-in voltage, and control DC power supply (Vcc) reaches the representative value voltage of PFC chip definition to multiplier input (Mult FP) output of PFC chip.
2. the output over-voltage protection circuit of pfc circuit according to claim 1, it is characterized in that: in described ON-OFF control circuit, include the adjustable shunting a reference source of one or three ends device (U1), the reference voltage end of described three ends adjustable shunting a reference source devices (U1) connects the connected node between the described divider resistance (R6, R7), plus earth, negative electrode connect the base stage of a positive-negative-positive triode (Q1); The emitter of described triode (Q1) connects described DC power supply (Vcc), and collector electrode connects multiplier input (Mult FP) of PFC chip.
3. the output over-voltage protection circuit of pfc circuit according to claim 2 is characterized in that: be connected with filter capacitor between the reference voltage end of described three ends adjustable shunting a reference source devices (U1) and ground.
4. the output over-voltage protection circuit of pfc circuit according to claim 3; it is characterized in that: the negative electrode of described three ends adjustable shunting a reference source devices (U1) connects on the one hand the base stage of described triode (Q1) through a resistance (R4), connects described DC power supply (Vcc) through another resistance (R2) on the other hand.
5. the output over-voltage protection circuit of pfc circuit according to claim 4 is characterized in that: be in series with divider resistance between the emitter of described positive-negative-positive triode (Q1) and the DC power supply (Vcc) or between multiplier input (Mult FP) of collector electrode and PFC chip; Also be in series with switching diode (D2) between the collector electrode of triode (Q1) and multiplier input of PFC chip (Mult FP).
6. television set with the described overvoltage crowbar of claim 1; comprise PFC chip and DC power supply (Vcc); it is characterized in that: between multiplier input (Mult FP) of described DC power supply (Vcc) and PFC chip, be connected with an ON-OFF control circuit; the voltage output end of PFC chip (VIN) is through resistance pressure-dividing network (R6; R7) ground connection; divider resistance (R6; R7) connected node between links to each other with the control end of described ON-OFF control circuit; when the output voltage of PFC chip is higher than limit value; the control end voltage of ON-OFF control circuit is at described divider resistance (R6; R7) effect is issued to its cut-in voltage value, and control DC power supply (Vcc) reaches the representative value voltage of PFC chip definition to multiplier input (Mult FP) output of PFC chip.
7. television set according to claim 6, it is characterized in that: in described ON-OFF control circuit, include the adjustable shunting a reference source of one or three ends device (U1), the reference voltage end of described three ends adjustable shunting a reference source devices (U1) connects the connected node between the described divider resistance (R6, R7), plus earth, negative electrode connect the base stage of a positive-negative-positive triode (Q1); The emitter of described triode (Q1) connects described DC power supply (Vcc), and collector electrode connects multiplier input (Mult FP) of PFC chip.
8. television set according to claim 7 is characterized in that: be connected with filter capacitor between the reference voltage end of described three ends adjustable shunting a reference source devices (U1) and ground.
9. television set according to claim 8, it is characterized in that: the negative electrode of described three ends adjustable shunting a reference source devices (U1) connects on the one hand the base stage of described triode (Q1) through a resistance (R4), connects described DC power supply (Vcc) through another resistance (R2) on the other hand.
10. television set according to claim 9 is characterized in that: be in series with divider resistance between the emitter of described positive-negative-positive triode (Q1) and the DC power supply (Vcc) or between multiplier input (Mult FP) of collector electrode and PFC chip; Also be in series with switching diode (D2) between the collector electrode of triode (Q1) and multiplier input of PFC chip (Mult FP).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2006200874340U CN2935667Y (en) | 2006-07-28 | 2006-07-28 | Output overvoltage protection circuit of PFC circuit and TV set equipped with the circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2006200874340U CN2935667Y (en) | 2006-07-28 | 2006-07-28 | Output overvoltage protection circuit of PFC circuit and TV set equipped with the circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2935667Y true CN2935667Y (en) | 2007-08-15 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2006200874340U Expired - Fee Related CN2935667Y (en) | 2006-07-28 | 2006-07-28 | Output overvoltage protection circuit of PFC circuit and TV set equipped with the circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2935667Y (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101778513A (en) * | 2010-02-05 | 2010-07-14 | 海洋王照明科技股份有限公司 | LED flow equalizing control circuit, LED driver module and navigation aiding light |
| CN102856876A (en) * | 2012-09-25 | 2013-01-02 | 广东易事特电源股份有限公司 | Anti-misreport island detection system |
| CN104506027A (en) * | 2014-12-26 | 2015-04-08 | 广东威创视讯科技股份有限公司 | Output voltage overshoot suppresser for PFC (power factor correction) circuit and power supply circuit with same |
-
2006
- 2006-07-28 CN CNU2006200874340U patent/CN2935667Y/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101778513A (en) * | 2010-02-05 | 2010-07-14 | 海洋王照明科技股份有限公司 | LED flow equalizing control circuit, LED driver module and navigation aiding light |
| CN101778513B (en) * | 2010-02-05 | 2013-06-12 | 海洋王照明科技股份有限公司 | LED flow equalizing control circuit, LED driver module and navigation aiding light |
| CN102856876A (en) * | 2012-09-25 | 2013-01-02 | 广东易事特电源股份有限公司 | Anti-misreport island detection system |
| CN102856876B (en) * | 2012-09-25 | 2015-10-21 | 广东易事特电源股份有限公司 | A kind of Anti-misreport island detection system |
| CN104506027A (en) * | 2014-12-26 | 2015-04-08 | 广东威创视讯科技股份有限公司 | Output voltage overshoot suppresser for PFC (power factor correction) circuit and power supply circuit with same |
| CN104506027B (en) * | 2014-12-26 | 2017-05-17 | 广东威创视讯科技股份有限公司 | Output voltage overshoot suppresser for PFC (power factor correction) circuit and power supply circuit with same |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20070815 |